Newer elevator installations can be switched from an operating mode to a standby mode, which is occasionally also termed a sleep mode, if the elevator installation has not been used for a certain period of time.
The energy consumption of an elevator installation is highest when it is in the operating mode and in a working state, i.e. when an elevator car after a request call executes an empty trip to a loading station or a passenger trip.
The energy consumption of the elevator installation is less when the elevator installation is still in the operating mode, but in a pause state. If the elevator installation is in the pause state, then it can be brought to the working state virtually free of delay.
The energy consumption is even less when the elevator installation is in the standby mode and thus to a certain extent sleeps. The elevator installation is then usually separated from its principal energy source, for example domestic mains, and, depending on the respective form of embodiment, connected with an auxiliary energy source, for example the supply of a bus system. In that case the bus system can be realized as a Biobus or LON bus system. In the standby mode substantially only basic functions are maintained in order to guarantee the necessary safety and to create the precondition that the elevator installation can be returned, in a beneficial period of time, from the standby mode to the operating mode. If the elevator installation is to be wakened from the standby mode and brought to the operating mode then it achieves the operating mode usually only after a certain delay time.
A greater part of the energy consumed in total by an elevator installation, namely to over 50%, is apportioned to the time periods in which the elevator installation remains in the standby mode. A reduction in the energy consumption during the operating mode is usually not significant. During the working state it can be realized only to a limited extent, since elevatoring of a load requires a non-reducible amount of energy even when all losses, such as, for example, friction which occurs, are reduced. During the pause state the energy consumption is indeed smaller, but cannot further reduce as desired, because the elevator installation always has to be ready for use without time delay.
The energy consumption of an elevator installation can thus often be perceptibly reduced only when the energy consumption in the standby mode is considerably decreased and, in particular, without the time requirement for re-entry into the operating mode thereby rising to an unacceptable extent. If this time requirement for wakening from the standby mode is kept small then also the operating criteria in which the elevator installation is disposed in the pause state can be appropriately changed and the elevator installation thereby kept longer in the standby mode without user friendliness with respect to waiting times after a request call of the elevator car being substantially impaired.
A safety device is known from patent document JP 04 327 475-A by which, for the purpose of energy saving, there shall be avoidance of interruption of the current feed from a mains to an elevator installation as long as a passenger is in the elevator car. The safety device comprises a lamp which is in operation only when a passenger is in the elevator car. There is concerned in this connection a device which does not allow efficient management of an elevator installation.